An approach to (4-fluoroalkyl-1-alkyl-1H-pyrazol-3-yl)methylamines

Deoxofluorination of (Hetero)aromatic Acids

“…It is important to mention that, in spite of previous literature precedents on deoxofluorination of (hetero)­aromatic acids, − none of products 2a – 65a synthesized here were ever obtained by this method before. It seems that even today, after almost 60 years since the discovery, this powerful synthetic strategy has not realized its full potential yet.…”

“…Indeed, in 1960, Engelhardt developed deoxofluorination of aromatic acids with sulfur tetrafluoride to obtain the corresponding trifluoromethylated products (Scheme ). Subsequently, this approach was used by other groups for the synthesis of trifluoromethyl-substituted pyridines, furans, thiazoles, uracils, pyrazoles, quinolones, etc . One of the biggest contributions to the field came from the school of the Soviet Union chemists, led by Yagupolskii .…”

Deoxofluorination of Aliphatic Carboxylic Acids: A Route to Trifluoromethyl-Substituted Derivatives

“…During the recent decade, sulfur tetrafluoride has been gaining popularity in both academic laboratories and industrial institutions . From the practical aspect, the use of an autoclave made of Hastelloy nickel alloy was needed.…”

Regioselective synthesis of pyrazoles fused with heteroaliphatic amines at the [3,4-c] edges

“…In an attempt to obtain 7, aldehyde 6 was reduced with NaBH 4 ; however, the reaction resulted in the formation of hemiaminal 8 in 46% yield. On the contrary, catalytic hydrogenation of 6 gave alcohol 9 (84%), 14 which was treated with hydrazine hydrate in 2-propanol to give the target compound 7 in 78% yield. Mesylation of 7 was accompanied by cyclization, leading to the 2,4,5,7-tetrahydropyrrolo[3,4-c] pyrazole derivative 10 (62%).…”